Author Topic: Sturmey Archer Hub Dynamo (Read 8033 times)

clarion · « **on:** 16 May, 2012, 01:01:07 pm »

I suspect I know that the answer to this is 'No', but I'll ask anyway:

I have a Sturmey Archer 3-spd with integrated hub dynamo. The period lights are a bit dim, to say the least (though I could uprate to halogen). Can I run a modern LED light off this unit? If not, can I do it with some kind of mod?

Thanks.

Pickled Onion · « **Reply #1 on:** 16 May, 2012, 01:20:31 pm »

Google suggests you almost certainly can - do you know what model it is?

More to the point, what ~~bulb~~ lamp is in the period lights? If this is the restoration project you mentioned a while back, it would be a shame to put modern lights on it, could the ~~bulb~~ lamp be changed to something with modern efficiency keeping the original ~~lamp~~ luminaire?

The old SA Dynohubs were not very efficient in terms of work to electrical power, but they did give a decent output, particularly at low speeds.

LittleWheelsandBig · « **Reply #2 on:** 16 May, 2012, 01:35:37 pm »

Modern halogens won't work well, the Dynohub voltage is too low but LEDs will be fine. You'd probably find that replacement LED bulb (do they still make them?) would be ok. Some of them were designed to use quite low voltages.

clarion · « **Reply #3 on:** 16 May, 2012, 01:43:44 pm »

ISTR the hub is an AG, but I may well be wrong.

I was thinking along the lines of a Cyo, as that is nice & bright, but has classic looks like an old Miller light.

LittleWheelsandBig · « **Reply #4 on:** 16 May, 2012, 01:50:05 pm »

I think an Oz friend of mine is running a Cyo from an ancient SA Dynohub.

clarion · « **Reply #5 on:** 16 May, 2012, 01:51:04 pm »

That's useful to know, thanks. Would you mind asking if it works straight from the source or if there has been Kleverness inserted?

tiermat · « **Reply #6 on:** 16 May, 2012, 01:52:09 pm »

Quote from: clarion on 16 May, 2012, 01:43:44 pm

ISTR the hub is an AG, but I may well be wrong.

I was thinking along the lines of a Cyo, as that is nice & bright, but has classic looks like an old Miller light.

You are right, AG, 3 speed + dyno (if it's the one on the EB)

LittleWheelsandBig · « **Reply #7 on:** 16 May, 2012, 02:06:55 pm »

Knowing Stimpy as I do, there would be no cleverness involved.

clarion · « **Reply #8 on:** 16 May, 2012, 02:18:15 pm »

Good enough for me.

Kim · « **Reply #9 on:** 16 May, 2012, 02:26:52 pm »

As long as the dynamo's putting out AC (can't imagine why it wouldn't), the Cyo should be happy enough.

Pickled Onion · « **Reply #10 on:** 16 May, 2012, 02:42:08 pm »

Quote from: LittleWheelsandBig on 16 May, 2012, 01:35:37 pm

Modern halogens won't work well, the Dynohub voltage is too low but LEDs will be fine. You'd probably find that replacement LED bulb (do they still make them?) would be ok. Some of them were designed to use quite low voltages.

Agreed, apart from it's not voltage that's low, it's the current. SA hubs were (nominally) 6V (most common), 8V and 12V but 0.25A (modern hubs are 0.5A). As they are constant current devices, if you put in a 6V/0.5A bulb the voltage will drop to 3V. That's probably what's happened here, someone has replaced with the wrong rating bulb which will be unacceptably dim. If you can source the correct rating it may well be sufficient.

Sheldon was a bit of SA fan, and has a description of his electrickery and also service instructions for the AG model.

GrahamG · « **Reply #11 on:** 16 May, 2012, 03:00:25 pm »

Quote from: LittleWheelsandBig on 16 May, 2012, 02:06:55 pm

Knowing Stimpy as I do, there would be no cleverness involved.

Stimpy. Says it all

GavinC · « **Reply #12 on:** 17 May, 2012, 12:27:54 pm »

I'm running a Cyo and Smart LED rear light from a 60's Sturmey GH6 front Dynohub on my Moulton Deluxe and it works perfectly.

Can't see any reason why an AG or FG geared hub/dynohub would be any different.

There was no cleverness invovled in setting it up - I just connected the two wires from the Cyo to the two connector posts on the hub and the rear light to the Cyo as normal. Simples.

If you want a front light with vintage looks, what about this new LED light from B&M? Not as bright as a Cyo (I think it's basically a rebodied Lyt), but it looks the ticket if you're after something to replace an old Miller front lamp.

andrew_s · « **Reply #13 on:** 17 May, 2012, 12:49:18 pm »

The Cyo is also available in a silver finish for vintage looks

GavinC · « **Reply #14 on:** 17 May, 2012, 01:01:15 pm »

Quote from: andrew_s on 17 May, 2012, 12:49:18 pm

The Cyo is also available in a silver finish for vintage looks

Yes, I have the silver one. But IMO the painted matt silver finish of the Cyo doesn't look quite as convincing on an old bike as the chromed finish of the new Classic (and the old Retro halogen model).

OTOH, choosing a light for it's appearance rather than it's ability to provide illumination is probably a bit daft.

clarion · « **Reply #15 on:** 17 May, 2012, 01:26:37 pm »

To be fair, buying a three speed rod-braked roadster to ride from London to Brighton three times a year could be regarded as somewhere on the spectrum of daft.

Cudzoziemiec · « **Reply #16 on:** 17 May, 2012, 01:28:06 pm »

But daft in an enlightened eccentric way.

clarion · « **Reply #17 on:** 17 May, 2012, 01:29:17 pm »

I'd like to think so. On the descents, I may well think otherwise.

Cudzoziemiec · « **Reply #18 on:** 17 May, 2012, 02:34:09 pm »

I'm not familiar with the terrain between London and Brighton - will be going over, and therefore down, Ditchling? I think I've already mentioned that when I was 15 or so I used to ride a 1950s Philips roadster with a 3-speed SA and rod brakes, a long-term loan from a kindly, elderly neighbour. <moment of reminiscence for several good neighbours> Curiously I don't remember much up-hill struggling but I guess when you're a teenager you just do it, I do remember various downhills were you really relied on the awareness of others as there was no way of actually stopping. But I never crashed it, so it worked!

clarion · « **Reply #19 on:** 17 May, 2012, 02:47:57 pm »

Not Ditchling. The veteran vehicles wouldn't manage it. Neither would I, but that's of no consequence.